Polyploidization is thought to be an important driving force in evolution as it increases the genetic material on which mutation and selection can act. In the Amazon molly, Poecilia formosa, triploid genotypes can be found in the field and frequently arise from diploid breeding stocks, a tetraploid individual, however, was so far never documented. Here, we report the first tetraploid Amazon mol...

The purpose of this paper is to discuss the trading system in the inter-war period concerning the Japanese Empire by means of border effect analysis in the gravity model. The results show sizeable and steadily increasing trading bloc border effects from the 1910s through the 1930s. This sizeable border effect might have resulted from many possible factors: trade diversion and creation due to in...

Figure 1. Sequence alignments of PA200 homologs. The sequences of PA200 homologs were aligned with the program MegAlign using the clustal method (DNASTAR).The sequence of human PA200 has been constructed from analysis of the human genome and from the cDNA KIAA0077. Tim Formosa (University of Utah) recently sequenced the putative intergenic region between BLM3 and YFL006 and found an additional ...

In animals, supernumerary chromosomes and their evolution have mostly been studied in sexual reproducing species. In the present study, for the first time, the natural distribution and stability of supernumerary microchromosomes were investigated in the unisexual fish species Poecilia formosa. Natural habitats throughout the range of P. formosa were screened for the presence of microchromosomes...